tty: serial: exar: generalize RS485 setup

Move the non-board-specific part of the RS485 initialization from
iot2040_rs485_config function to a new generic function used also for
other boards.
This allows using TIOCGRS485 and TIOCSRS485 on boards (such as mPCIe
serial IO modules) which are hard-wired to RS485 or have jumpers for
their configurations.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c
index 38af306..102e059 100644 (file)
--- a/drivers/tty/serial/8250/8250_exar.c
+++ b/drivers/tty/serial/8250/8250_exar.c
@@ -272,8 +272,32 @@ static int xr17v35x_register_gpio(struct pci_dev *pcidev,
        return 0;
 }
 
+static int generic_rs485_config(struct uart_port *port,
+                               struct serial_rs485 *rs485)
+{
+       bool is_rs485 = !!(rs485->flags & SER_RS485_ENABLED);
+       u8 __iomem *p = port->membase;
+       u8 value;
+
+       value = readb(p + UART_EXAR_FCTR);
+       if (is_rs485)
+               value |= UART_FCTR_EXAR_485;
+       else
+               value &= ~UART_FCTR_EXAR_485;
+
+       writeb(value, p + UART_EXAR_FCTR);
+
+       if (is_rs485)
+               writeb(UART_EXAR_RS485_DLY(4), p + UART_MSR);
+
+       port->rs485 = *rs485;
+
+       return 0;
+}
+
 static const struct exar8250_platform exar8250_default_platform = {
        .register_gpio = xr17v35x_register_gpio,
+       .rs485_config = generic_rs485_config,
 };
 
 static int iot2040_rs485_config(struct uart_port *port,
@@ -306,19 +330,7 @@ static int iot2040_rs485_config(struct uart_port *port,
        value |= mode;
        writeb(value, p + UART_EXAR_MPIOLVL_7_0);
 
-       value = readb(p + UART_EXAR_FCTR);
-       if (is_rs485)
-               value |= UART_FCTR_EXAR_485;
-       else
-               value &= ~UART_FCTR_EXAR_485;
-       writeb(value, p + UART_EXAR_FCTR);
-
-       if (is_rs485)
-               writeb(UART_EXAR_RS485_DLY(4), p + UART_MSR);
-
-       port->rs485 = *rs485;
-
-       return 0;
+       return generic_rs485_config(port, rs485);
 }
 
 static const struct property_entry iot2040_gpio_properties[] = {